A new invention from Germany’s University of Mainz is not only the world’s smallest engine by an enormous margin, it may have broken a theoretical limit for engine efficiency. The device, a so-called “atomic engine,” produces power thanks to the movements of just a single atom trapped and manipulated. It’s an incredible achievement that, while not particularly useful for engineering in the short term, could revolutionize our understanding of the quantum world. Plus, it’s really neat.
Despite its size, this engine is actually patterned after one of the simplest possible engine designs, called a Carnot engine. This idea basically describes any engine that creates mechanical work out of the transfer of heat from one place to another — imagine if your thermos could power a little electrical generator for an LCD temperature display, simply off the slow loss of heat to the atmosphere. This “engine” holds a single calcium ion (charged atom) trapped in a cone of electromagnetic energy called a Paul trap. At the narrow end of the cone the device applies a heating laser that adds energy to the atom’s electrons, causing them to become more repulsive to the positively-charged nucleus and orbit further out. Since the atom is squeezed so tightly at the narrow end, this expansion causes it to rush along the length of the cone toward the wide end — where it meets a cooling laser.To read more, click here.